Arizona Petrified Forest National Park map and highlights

Above right: These  petrified stumps tell the story of the land long ago, of a time two  million years ago when majestic pine trees graced the riverbanks.   

Below: Gleaming like quartz, petrified wood, when polished, shows amazing crystal-like patterns.   

Petrified Forest, Arizona   

Established: 1962   Acreage: 93,493   

Located in northeast Arizona, this high, dry tableland was once a  vast flood plain crossed by many streams. To the south, tall, stately  pine-like trees grew along the headwaters. Crocodile-like reptiles, huge  fish-eating amphibians and small dinosaurs lived among a variety of  plants and animals that are known today only as fossils.   

About 200 million years ago the tall trees fell and were washed  by swollen streams into the floodplain, and were then covered by silt,  mud and volcanic ash. This blanket of deposits cut off oxygen and slowed  the decay of the logs. Gradually, silica-bearing ground waters seeped  through the logs and, little by little, replaced the original wood  tissues with silica deposits. The process continued, the silicas  hardened and the logs were preserved as petrified wood. The variety of  colors in the wood was created by the presence of iron and manganese  oxides.   

Later, the area sank, was flooded, and covered with freshwater  sediments. Afterwards the area was lifted above sea level, which caused  the giant logs to crack. Wind and water began to wear away the hardened  sediment, exposing the petrified trees and fossilized animal and plant  remains. Today the forces of erosion continue to wear down the sediments  and reach for the logs and other remains still buried beneath the  surface.   

A new dimension was added to the Petrified Forest fossil record  in 1985 with the discovery of the world's oldest dinosaur skeleton near  Chinde Point. Nicknamed Gertie, this plant-eating Plateosaur dates back  225 million years, to the dawn of the Age of Dinosaurs in Triassic  times. Although the size of a German shepherd dog, Gertie ranks as an  ancestor of the giant brontosaurs.   

The Petrified Forest tells the story of human existence as well.  In the 1300s, a group of Anasazi Indians lived near the Puerco River in a  76-room pueblo, but Spanish explorers found the place abandoned when  they arrived in 1540. In the mid-1800s, US Army mappers and surveyors  explored the area and returned East with tales of a remarkable 'painted  desert and its trees turned to stone.' Soon ranchers, farmers and  sightseers made their way to Arizona. For a time the wood was collected  for souvenirs and commercial purposes, but by 1900 local citizens  recognized that the supply of petrified wood was not endless and called  for the area to be preserved.   

Petrified Forest, Arizona on the map. National Park Petrified Forest (Arizona state) on the map of US